Mechanical Design, Fabrication, and Installation

Transcription

1 Mechanical Design, W.J. Llope Rice University System MRPCs Tray Design Electronics Installation STAR TOF excellent complicated new & complicated simple STAR MTD excellent simple commodity complicated Outline: MTD tray mechanical design MTD11 prototype assembly MTD11 testing MTD9 and MTD11 in STAR Full System design and installation MTD9 is the older run-9/10 prototype MTD11 are new prototypes for run-11 Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

2 Assumed MRPC Dimensions for MTD11 Prototypes Tsinghua MRPCs were 93cm long Prefer 91.5cm Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

3 MTD11 Tray Design (Exploded View) no reason known (yet) why the MTD11 tray design cannot be final for full system Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

4 MTD11 Tray Design (Top View) MRPC footprint inner glass stack = active area Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

5 Initial Design for MTD11 Stacking in STAR The three MTD11 Trays mount directly onto BEMC PMT boxes The Trays overlap so that the MRPC active regions meet end-to-end in Z lower row of trays bolt to unistrut on the BEMC PMT boxes upper row of trays bolt to the lower row of trays this won t work for the full system more on this later in this talk Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

6 The MTD11 Project Rice and UT-Austin received ~155k$ STAR R&D funds for a MTD patch for Run-11 Design and fabricate three production prototype mechanical structures We actually built four full trays (one still at UT-Austin) Two Tsinghua MRPCs (two with μm gaps, 58cm 93cm outer) Two USTC MRPCs (6 250 μm gaps & μm gaps, 58cm 91.5cm outer) Develop and fabricate new front-end electronics: MFTB, MINO, & MTRG Assemble & test the trays with final electronics Detectors arrived December 13, 2010 & were installed immediately Being operated throughout the run gain operational experience and study timing & triggering performance Develop new tight timing (VPD+MTD) triggers Also accomplished: MTD9 moved to a different location, operating throughout the run New MTD-specific THUB and DAQ interface On the following slides: Assembly and Test of MTD11 trays at UT-Austin Installation and operation in STAR during present Run-11 Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

7 MTD11 Tray Assembly Tray top (holds electronics) is complicated Fabricated at Oaks Precision in Houston Delivered to UT-Austin in the back seat of my car Top and frame (upside down) frame underside of top upper spacer big hole (covered by MFTB) top tack-welded to (welded) frame, sealed with DC730 freon-resistant sealant bottom bolts to frame in countersunk holes, also sealed with DC730 Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

8 MTD11 Tray Assembly MRPCs inside the tray bottom of MRPC is flush with the bottom of the tray correct upper spacer thickness is thus important! side spacers hold MRPC laterally w.r.t. the frame HV wiring connected to bulkhead connector Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

9 MTD11 Tray Assembly (Connections Schematic) UT will make the signal pigtails and ship them to China/India Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

10 MTD11 Tray Assembly Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

11 MTD11 Test Results at UT-Austin Hit patterns Untriggered cosmics freon-only 6 250μm gaps: HV = ±7300V 5 250μm gaps: HV = ±6300V Read-out via full chain of final electronics reasonable noise rates (strip area = 331 cm 2, so <0.5 Hz/cm 2 ) no dead channels Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

12 MTD9 and MTD11 Trays at BNL, December 2010 MTD9 & MTD THUB Three MTD11 trays (craned into place) backleg 1 backleg 26 From East side looking West Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

13 Run 11 Online hit patterns (untriggered) and HV information online hit patterns look reasonable (3 MTD11 trays 2 strip ends 2 signal edges) low rate per 1M events because this is p+p ( s NN = 500 GeV) MTD11 trigger still being developed (see Lijuan s talk in this workshop) HV monitoring line 1: μm gap MTD11 trays, ±7200V line 2: μm gap MTD11 tray+mtd9, ±6200V Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

14 Geometry of the Full System also see packs over the top 2 5-packs just under equator 11 3-packs below 118 MTD trays total N/S & E/W symmetric implemented in STAR geant simulations framework Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

15 Full System Installation Scheme above STAR BEMC PMT boxes below STAR BEMC crates Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

16 Full System Installation Scheme The mounting scheme for the MTD full system trays is actually a difficult problem! MTD trays must mount on top of BEMC PMT boxes access to these some number of these boxes is needed during every shutdown to repair BEMC channels typically this work is done by laying down on neighboring PMT boxes this implies that 2-3 backlegs of MTD trays would need to be removed to access a single BEMC box! Scheme used in Run-11 worked, and was the simplest possible for us, but it would be a nightmare for a full system tray positioning is a little too sloppy because of imprecise positioning of unistrut nuts difficult to install the upper layer of trays onto lower layer of trays too much work for STSG (Bob Soja and his expert technicians) to remove/reinstall MTD trays too much cabling (dis)connecting & stresses on MTD modules increased failures & gas leaks? There is another problem too - how do we get access to a random tray on top of STAR? one cannot simply walk on the MTD layer like one can walk on the PMT boxes how do we replace a cable or sniff for gas leaks on a random tray when everything is installed?!? And yet another problem are obstructions hanging from the boxes below STAR This is clearly going to be the hardest part of the total system design. Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

17 Full System Installation Scheme We want: MTD (de)installation by STSG to be rapid, repeatable, and safe Reasonably quick access any MTD tray at any time Efficient access to any EMC PMT box w/ minimal MTD deinstallation Some way around the obstructions below STAR w/out moving those obstructions Several face-to-face meetings have been held to discuss the various issues MTD reps: Bill Llope, Lijuan Ruan, Zhangbu Xu BEMC rep: Oleg Tsai STSG reps: Bob Soja, John Scheblein STAR Operations Manager: Bill Christie Most recent meeting was on 2/22/2011 Summary & action items: General agreement on the basic idea which I will describe on the following slides consider above STAR and below STAR cases separately Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

18 Full System Installation Scheme new approach: Make mounting more complicated to make integration easier unistrut mounts to two layers of cross-pieces use available space between backlegs install diamond plate covers over the top (heat retension?) (J. Scheblein & WJL) Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

19 Full System Installation Scheme 2 pack of MTD trays cross-piece pair unistrut BEMC PMT box Two PMT boxes per backleg one 2 pack on each PMT box 5 th MTD tray joins two 2 packs Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

20 Full System Installation Scheme (Above STAR case) movie: Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

21 Under STAR not a lot of room down there not enough slack in BEMC cabling to move these crates only viable option known is to widen the hangars Full System Installation Scheme (Below STAR case) Other items: fittings and fixtures should be plug and play (limit # of small nuts/bolts) allow for foam filler pieces between PMT boxes locate local tray testing and storage area locate space and define fixtures for 2-pack assembly in the AB/WAH Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

22 Summary and Conclusions MTD11 prototype project has been successful so far Fabricated trays and USTC & Tsinghua MRPCs fit together nicely Test results after fabrication look very good Detectors installed on-time. Collecting untriggered data throughout Run-11 Hit patterns and noise rates in STAR are reasonable Looking forward to resolution results & add l development of timing triggers MTD11 tray design is final if MRPC footprint stays at 58cm 91.5cm 3cm Negative HV side has the signal pigtails UT will produce the pigtails (Jo brought examples to this meeting) The critical issues in terms of system design involve installation scheme Above STAR: approach with semi-permanent covers Below STAR: widen the hangars, leave BEMC crates where they are Still need to optimize these designs but the basic idea is in place I think... Workshop on STAR MTD Production and Related Physics, Hefei, Anhui, China, March 30,

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